Fuse plug



July 1 1924. 1,499,484

W. L. SMITH Original Filed Oct. 25, 1921 luvs/v TOE WEBB L. NHTH Patented July 1, 1924.

JPATENT OFFICE.

WEBB Lf'SMITI-I, OF SAN FRANCISCO, CALIFORNIA.

FUSE PLUG.

Application filed October 25,1921, Seria1No.'510,'228. Renewed May 10, 1924.

To all whom it may concern Be it known that I, WVEBB L. SMrrrI, a citi- Zen of the United States, and a resident of the city and county of San Francisco, State of California, have made a new and useful invention, to wit, Improvements in Fuse Plugs; and I do hereby declare the following to be a full, clear, concise, and exact description of the same.

This invention relates particularly to a safety fuse plug.

An object of this invention is to construct a fuse plug with means whereby the fuse element may be quickly and easily replaced. A still further object of this invention is to provide a plug with a single fuse element that will function as a double fuse element. A further object of this invention is to provide a fuse plug that will be superior in point of simplicity and inexpensiveness of construction, positiveness of operation, facility and convenience in use and general efiiciency as contrasted with fuse plugs of a similar character. Other objects and advantages will appear as this description progresses.

In this specification and the annexed drawings, the invention is illustrated in the form considered to be the best, but it is to be understood that the invention is not limited to such form, because it may be embodied in other forms; and it is also to be understood that in and by the claims following the description, it is desired to cover the invention in whatsoever form it may be embodied.

In the accompanying one sheet of draw- I Fig. 1 represents a vertical section through the plug constructed in accordance with my invention.

Fig. 2 represents a plan View of Fig. 1.

Fig. 3 represents a view of the under side of Fig. 1.

In detail the construction illustrated in the drawings comprises a plug element molded from bakelite, hard rubber or any other equivalent heat resisting and non-conducting composition. The plug consists of the enlarged annular head portion 1, body portion 2 and reduced end projection 3. The enlarged head portion 1, in accordance with standard practice, would be appropriately knurled or finished to facilitate its being laced in or removed from a plug socket.

e body portion 2 of the said plug is molded or otherwise provided with a rolled thread 4 thereon of astandard pitch so as to conform with standard practice. The plug is bored axially at 5 and 6 with holes of different diameters so as to provide a central opening therethrough. A lateral opening 7 passes diametrically through the plug, adj acent the shoulder 31 formed between the reduced end 3 and the threaded body portion 2.

A fusible element or fuse wire 8 is adapted to be placed in said transverse opening so that the respective ends of said fuse wire project beyond the circumference of the reduced end 3. A suitable screw 9 is adapted to be mounted in the central opening 6 so that the shank thereof will pass to one side of the laterally placed fuse wire 8 and a suitable nut 10 is placed in threaded engagement with said screw and advanced thereon so as to contact wit-h the said fuse wire and clamp it between the face of said nut and the base of the opening 5. This particular method of clamping the fuse wire between the nut and base of the opening 5 binds it rigidly in place yet permits the screw 9 to be rotated sufficiently so that the fuse wire 8 may be removed for replacement. A metal annulus 11 suitably stamped with rolled threads is placed in engagement with the threaded portion of the body 2 so that the annular shoulder 12 on said annulus will pass around and superficially contact with the projecting ends of the fuse element 8 to thus complete a circuit when the fuse plug is mounted in a socket.

A fuse plug of the character described may be properly classified of the renewable type whereby a person relatively unskilled in apparatus electrical might replace a burned out fuse with a new element.

In order that the fuse might conform in all respects as a safety device, the opening 5 would be filled with wax or the like to prevent tampering with the fuse element or its binding means. For the purpose of replacement, the wax filling medium may be easily removed and the respective parts changed about at the will of the operator.

Having thus described this invention what I claim and desire to secure by Letters Patent is:

1. A device such as described comprising an externally threaded plug having a central bore therein; a fuse element arranged transversely in said plug and passing through said bore; a fuse binding element adapted to engage said fuse in said bore and a metal an nulus adapted to engage the threaded porat the opposite ends of said plug; a fuse element adapted to be positioned transversely Within said plug and to pass diametrically through said central passage adjacent the shoulder formed between the diflering diameters; a screw adapted to be inserted into said smaller diameter passage; a nut adapted to engage said screw and to clamp said fuse element against said aforementioned shoulder and an annulus adapted to engage the threaded portion of said plug and contact With the opposite ends of said fuse element.

In testimony whereofilhave hereunto set my hand at San Francisco, California, this 20th day of Oct. 1921.

lVEBB L. SMITH In presence of LINCOLN V. JOHNSON. 

